Heated insole construction

ABSTRACT

An electrically heated insole construction adapted to be fitted into a shoe or boot, the insole having a layer of plastic mesh material with the openings in the mesh providing air insulation spaces, and a layer of plastic electrically insulated material overlying the mesh material in a toe portion of the insole and having an electrically conductive circuit printed thereon.

United States Patent [191 Gross et al.

[4 1 Sept. 16, 1975 1 HEATED INSOLE CONSTRUCTION [75] Inventors:Alexander Louis Gross, Aspen,

Colo.; Erik 0. Giese, Key Biscayne, Fla.

[73] Assignee: Comfort Products, Inc., Aspen,

22 Filed: Nov. 7, 1974 21 Appl. No.: 521,880

[52] US. Cl. 219/211; 36/2.6; 128/383; 219/523; 219/529; 219/536 [51]Int. Cl. H05B l/00; H05B 3/16 [58] Field of Search 219/211, 523, 528,529, 219/536; 128/383; 36/26, 43-44 [56] References Cited UNITED STATESPATENTS 1,430,404 9/1922 Radford 219/211 UX Pelosi 36/26 2,206,0297/1940 Daniels... 36/26 X 2,692,326 10/1954 Crowell 36/26 X 3,621,19111/1971 Comwel1..... 219/211 Primary Examiner-C. L. Albritton Attorney,Agent, or FirmPennie & Edmonds [5 7] ABSTRACT An electrically heatedinsole construction adapted to be fitted into a shoe or boot, the insolehaving a layer of plastic mesh material with the openings in the meshproviding air insulation spaces, and a layer of plastic electricallyinsulated material overlying the mesh material in a toe portion of theinsole and having an electrically conductive circuit printed thereon.

7 Claims, 5 Drawing Figures PATENTEU SEP 1 6 ms S'H'E'E uppl FIG. 4

FIG. 5

20' I7 [is HEATED INSOLE CONSTRUCTION I BACKGROUND OF THE INVENTIONVarious forms of insole constructions have been proposed in order thatboots, shoes and other footwear may be electrically heated. Examples ofsuch structures are illustrated in the following US Pat. Nos.1,275,451,. 1,430,404, 2,028,347, 2,692,326 and 3,621,191. Prior artconstructions as exemplified in these patents for the most part providefor electrical resistance elements in the form of conventional wiring tobe embedded in insoles with the result that heat, in addition to beingdirected to the bottom of theusers foot, is also directed to the sole ofthe shoe such that this heat is for the most part wasted. Since theprior art constructions depend upon power packs for the source ofelectric power and because the power packs have a limited capacity, theheat wasted in heating the sole of the shoe represents a substantialdrain on the limited capacity of the power pack. The use of plasticinsulation layers in heated insole constructions has been proposed inorder to reduce the flow of heat to the sole of the shoe. See forexample application Ser. No. 416,209 filed Nov. 15, 1973. Suchconstructions utilize conventional electrical wiring which wiring allowsheat to be radiated evenly around the circumference of the wiring suchthat only a small part of the heat is directed towards the users foot.

It is an object of our invention to provide for an electrically heatedinsole which assures that heat will be directed primarily towards thefoot of the user rather than towards the bottom sole of the shoe intowhich the insole is fitted thus making the best use of the limitedcapacity of the power pack.

GENERAL DESCRIPTION OF THE INVENTION Broadly, our invention comprises anelectrically heated insole having a heel area and a toe area which maybe fitted into the bottom of a shoe, boot, or other footwear. The insolecomprises in part a layer of plastic mesh material where the openings ofthe mesh form air insulation spaces. A layer of electrically insulativeplastic material overlies the layer of mesh material in the toe area ofthe insole and has an electrically conductive circuit printed on theside of the plastic layer opposite the plastic mesh material. In thismanner heat generated in the printed circuit when it is connected to apower source by electrical wiring will be directed towards the foot ofthe user and prevented by the air insulation spaces of the mesh materialfrom being conducted to the sole of the shoe. Preferably the mesh-likematerial comprises two layers of a fabric-like material knitted or wovenfrom a plastic monofiliment which layers are separated by corrugatedmonofiliment material. The monofiliment material extends across thewidth of the insole and forms grooves running the length of the insolethrough which electrical wiring may extend from the printed circuit tothe heel portion of the insole. A layer of a protective lining materialmay overlie the mesh material and the printed circuit to give a smoothprotective surface. A layer of pressuresensitive adhesive is applied tothe mesh-like material in order that the insole may be affixed into theshoe.

In a further form of the invention an additional foamlike plasticmaterial is interposed between the mesh material and the electricallyinsulative layer having the printed circuit to provide a further layerof insulation between the printed circuit and the sole of the shoe intowhich the insole is to be fitted.

In a still further form of the invention, a film of a heat sealablematerial is interposed between the mesh-like material and the layer ofpressure-sensitive adhesive and is heat sealed about its periphery tothe protective lining material which may also comprise a heat sealablematerial. In this manner the mesh-like material is encased by the heatsealable materials and thus further increases the insulation propertiesof the air spaces.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagrammatical view of anelectrically heated insole constructed according to the inventionillustrating the connection between the insole and a power pack carriedby a user;

FIG. 2 is a partial sectional top view of a heated insole constructionaccording to the invention;

FIG. 3 is an enlarged side sectional view of FIG. 2 taken along lines33;

FIG. 4 is a view similar to FIG. 3 of a second embodiment of a heatedinsole; and

FIG. 5 is a view similar to FIG. 3 of a third embodiment of a heatedinsole.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1,there is illustrated a heated insole 1 constructed according to theinvention connected by electrical wiring 2 and 3 to a power pack 4adapted to be mounted by a clip or other means to the belt of a user. Asshown the electrical wires 2 and 3 extend down the inside of the legs ofthe users trousers and are joined by means of a conventional plug andsocket arrangement 5 to wiring connecting with the insole. The batteriescontained in the power pack 4 are of the rechargeable type which may beconveniently recharged by mounting on a charging unit. When the powerpack is to be recharged, it is detached from the wires 2 and 3 byremoving a connecting plug 6 and moved to the charging unit. The amountof power withdrawn from the power pack and thus the amount of heat to begenerated by the heated insole is regulated by disconnecting andconnecting the plug 6. Batteries which are commercially available may berecharged 250 times or more and are sufficient to provide power forapproximately eight hours, the length of a working day during which theheated insoles would be operable.

The novel insole constructed according to the invention comprises aplastic mesh-like layer 10 preferably made of saran fiber comprising twolayers of fiber-like material 1 l and 12 which are separated by acorrugated monofiliment 13. As shown, a plurality of air pockets 14 areformed which reduce the convection flow of air between-the layers 11 and12.

An electrically insulative plastic layer 15 overlies layer 10 on the topportion of the insole and comprises a plastic layer 16 which may be of apolyester material having printed thereon a conductive circuit 17 overwhich a further layer 18 which is of the same material as layer 16extends. Circuit 17 in turn connects with lead wires 2 and 3'. The layer15 is affixed to the layer 10 by an adhesive 19. By utilizing aconductive circuit which is printed on the film 16 rather thanconventional resistance wiring, a greater effective surface area of theresistance circuit is created which improves the transfer of heat invertical directions.

Aprotective lining 20 is applied to the layer 15 by an adhesive 21. Thelining 20 may comprise a cloth material having a moisture absorbingcapacity or a vinyl material having a moisture-absorbing capacity andincluding a fungus retardant. The lining increases the comfort to theuser by providing moisture-absorbing capacity and also by providingsufficient friction for foot stabiltiy when engaged by the foot of theuser. In addition the lining provides a degree of protection to theprinted circuit, a degree of rigidity to the insole and serves toimprove the appearance of the insole.

The mesh-like layer 10 has a pressure-sensitive adhesive 22 on the lowerside thereof over which a protective layer of paper 23 extends. When theinsole is to be applied in a shoe, the protective layer of paper 23 ispeeled off of the adhesive 22 and the insole applied to the interior ofa shoe. Pressure of the users foot on the insole will be sufficient tothen affix the insole to the shoe.

As shown in FIG. 2 the electrically insulative layer 15 is shaped tocover only the toe area of the insole. This is because in practice ithas been found that under cold weather conditions discomfort arisesmainly from ones toes becoming too cold rather than other areas of thefoot, such as the heel or arch. It has been found that if the toes areheated, this is usually sufficient to provide the degree of heatnecessary to give the required degree of comfort while at the same timeeliminating any unnecessary heating of other areas of the foot whichwould result in excess draining of the capacity of the power pack.

The use of the layer of mesh-like material besides providing the airchambers 14 which improve the insulative effect of the material alsoprovides channels through which the wires 2' and 3' extend along thelength of the insole thus providing protection for the wiring. The wiresextend to the heel area of the insole and for a short exposed areabeyond the heel area and are adapted to be taped to the inside heel ofthe shoe. A short portion extends outside the shoe and is connected bythe plug assembly 5 to the wires 2 and 3.

FIG. 4 illustrates a further embodiment of the invention which isgenerally similar to that of FIG. 3 with the exception that a furtherlayer of plastic foam material 25 is interspersed between the layer ofmesh material and the layer of electrically insulative plastic material.This particular construction provides still greater insulation betweenthe printed resistance portions 17 supplying the heat and the soleportion of a shoe which need not be heated.

Referring to FIG. 5 a further form of an insole constructed according tothe invention is shown which differs from the constructions of FIGS. 3and 4 in that the lining 20 comprises a layer of vinyl plastic and inthat a further vinyl layer 26 is interspersed between the mesh-likelayer 10 and the pressure-sensitive adhesive layer 22. Layer 26 andlining 20' are heat sealed together along their peripheries such thatthe mesh-like layer 10 and spaces 14 are encased between the vinyl layer26 and the lining 20. This construction increases the insulativeproperties of the layer 10 by preventing flow of air into and out of thechambers 14 around the edges of the insole. At the same time, the vinyllayer 26 and lining 20' provide additional structure for holding thecomplete insole in assembled relation. A layer of adhesive 27 affixesthe vinyl layer 26 to the mesh-like layer 10.

We claim:

1. An electrically heated insole construction having a heel area and atoe area adapted to be fitted into a shoe, said insole constructioncomprising a layer of plastic mesh material with the openings in themesh material providing air insulation spaces, a layer of electricallyinsulative plastic material overlying said layer of mesh material in thetoe area of the insole, an electrically conductive circuit printed ontheside of said insulation material opposite said layer of plastic mesh,and electrical wiring connected to said printed circuit and adapted toextend to a source of electric power.

2. An electrically heated insole construction accord ing to claim 1wherein said plastic mesh material comprises two layers of fabric-likematerial separated by a spacing material and wherein said electricalwiring extends between said layers of fabric-like material.

3. An electrically heated insole construction according to claim 2wherein said spacing material comprises a corrugated monofilimentextending across the width of said insole and wherein said electricalwiring extends lengthwise of said insole in grooves formed by thecorrugation of the monofiliment.

4. An electrically heated insole construction according to claim 1having in addition a protective lining overlying said mesh material andsaid insulative material to provide a lining for said insole.

5. An electrically heated insole construction according to claim 4having in addition a layer of pressuresensitive adhesive on the side ofsaid plastic mesh opposite said insulation material whereby said insolemay be affixed in a shoe.

6. An electrically heated insole construction according to claim 5having in addition a layer of plastic foam material affixed to the sideof said electrically insulative material opposite said conductivecircuit.

7. An electrically heated insole construction according to claim 5wherein said lining layer comprises a heat sealable plastic film andhaving in addition a further heat scalable plastic film interposedbetween said layer of pressure-sensitive adhesive and said layer of meshmaterial and wherein the heat sealable plastic films are sealed togetherabout their peripheries.

1. An electrically heated insole construction having a heel area and atoe area adapted to be fitted into a shoe, said insole constructioncomprising a layer of plastic mesh material with the openings in themesh material providing air insulation spaces, a layer of electricallyinsulative plastic material overlying said layer of mesh material in thetoe area of the insole, an electrically conductive circuit printed onthe side of said insulation material opposite said layer of plasticmesh, and electrical wiring connected to said printed circuit andadapted to extend to a source of electric power.
 2. An electricallyheated insole construction according to claIm 1 wherein said plasticmesh material comprises two layers of fabric-like material separated bya spacing material and wherein said electrical wiring extends betweensaid layers of fabric-like material.
 3. An electrically heated insoleconstruction according to claim 2 wherein said spacing materialcomprises a corrugated monofiliment extending across the width of saidinsole and wherein said electrical wiring extends lengthwise of saidinsole in grooves formed by the corrugation of the monofiliment.
 4. Anelectrically heated insole construction according to claim 1 having inaddition a protective lining overlying said mesh material and saidinsulative material to provide a lining for said insole.
 5. Anelectrically heated insole construction according to claim 4 having inaddition a layer of pressure-sensitive adhesive on the side of saidplastic mesh opposite said insulation material whereby said insole maybe affixed in a shoe.
 6. An electrically heated insole constructionaccording to claim 5 having in addition a layer of plastic foam materialaffixed to the side of said electrically insulative material oppositesaid conductive circuit.
 7. An electrically heated insole constructionaccording to claim 5 wherein said lining layer comprises a heat sealableplastic film and having in addition a further heat sealable plastic filminterposed between said layer of pressure-sensitive adhesive and saidlayer of mesh material and wherein the heat sealable plastic films aresealed together about their peripheries.